Composite biomaterials such as composite hydrogels can be useful in a variety of applications including medical and biological applications. For example, they may be useful in therapeutic, tissue engineering, or cell culturing applications. In applications involving living cells, it is desirable to control the microenvironments around the cells, or to be able to modify the microenvironments for various purposes.
It has been reported that composites containing an interpenetrating polymer network (IPN) can be prepared through the formation of photo-crosslinked polymer networks, and the phase structure and morphology of an IPN determine its physical properties. See Peng et al., “Hydrogel-elastomer composite biomaterials: 3. Effects of gelatin molecular weight and type on the preparation and physical properties of interpenetrating polymer networks,” J. Mater. Sci.: Mater. Med. (2008) 19:997-1007 (“Peng”). Peng notes that most studies have been directed at understanding the impact of alterations in compositions and preparation chemistry on IPN structures, morphologies and properties, and controlling IPN morphology through changes in irradiation intensity, reaction temperatures and chemical structures have also been investigated.
The application of photochemically crosslinked composite hydrogels may be restricted in some cases. For example, 3-dimensional (3D) hydrogels with encapsulated cells are not compatible with photochemical techniques. Using enzymatically controlled crosslinking techniques may be better in some cases to provide implantable hydrogels encapsulated with cells.
Injectable hydrogels are also not compatible with photochemical crosslinking techniques. Enzymatically controlled crosslinking techniques may be better in some cases to provide an injectable composite hydrogel system for injection into a living organism.